Abstract In order to compare the applicability of water resource optimal allocation models with different objectives, including maximum agricultural water productivity, minimum agricultural irrigation loss and maximum net economic efficiency, in the middle reaches of the Heihe River Basin, we developed optimal water allocation models with fully considering the stochastic character of surface water. The multiindex comprehensive evaluation method and the entropy weighted model were introduced to evaluate the effectiveness of the three optimization models. Evaluation results show that the model of the maximum agricultural water productivity as the objective function in the irrigation area is more suitable for the water resources allocation requirements in the middle reaches of the Heihe River Basin from the comparison of the water resources utilization. Through optimization model with objective of maximum agricultural water productivity, the overall water consumption of the water allocation plan has decreased 334×108 m3, the irrigation water productivity has increased 0453 kg／m3, and the water costs have decreased by 421×107 Yuan. The obtained results verify the feasibility of the water resources optimization model.